Index fixture



RES.

M. L. BENJAMIN ET AL INDEX FIXTURE Filed Dec. 8, 1948 INVENTORS MILTON LBY R QNKLYN E-W/l/NEN June 17, 1952 Patented June 17, 1952 V ly'li E.Wihnefi; ai'ss'lii'or'tosaid'li Application December 8, 1948,.vSerial-No" 64,116 G'Clfiiiiis? (01. 90:57)" 1 l The: presentimprovements relating genefally as indicatedto an indexfixture are' norpabl x d ticularly concerned with an indexfixtiire' fgi'f 'detilojriillmachine to1s--and--the1ike wherein, for xamp veil this it is:;necessar-ytopredeterminedly-relatively to: tate alworkpiece and a-too1'-toposition the tanner for operation-upon by the latter; onejllustra tiveexample is: the milling of uniformlyspaced longitudinal slotsin'-contractible colletsand the like: wherein; after theformation ofglflesloh iti is necessary to index the col-let or milling. cutter forformingi the. nextslot; I I

It a primary: object of this invention toprovide an index fixture whichis accurately n dexed-through reciprocationoi the movable-element of afiuid-powei devicetherein,v Another object is to provide an indexfixture r v x V in which the rota-rymemberthereof operatively: Kgnoysftdthdfawings aindffirst fiio connected with a-ratchetwheeland-vpawl-mechaii ci'all'yt 'gS I Z'theft fthere'i's" shown nism isimmovably locked in indexed positiorisi q q fl i r fi s Ziaffdi by meansindependent:ofltheratchet pawlsr @{Pfi 3} Another object is-to'proyidea; fluid pressure actuated index-fixture inewhich: the movable elementof the fluid power-device when actuatedim one direction releases theaioresaid: locking: meansandi-positions one-pawl: for: engagement i withtheratchetwheetwhile another-*pawlhqlds- V H Y i dzbi otided wrth'the-wheeland; which element when. actuated im v centtlie' 'fiar'ige 9fdffii'ecfadja, an oppositedirectionmoves.the wheel tdanew c fi'dnendther'ofand w a lock nut Ill position th roug-h said one pawlgandiata-prethreaded onto the other end thereofi said-lock determinedrctative position of'the -ratchet wheel; nut beingiield; againstfit t'ifi. frmfl. adjusfedl permitsthe '1ocking;;meansto* engagether-wheelposition as by niea'ns of ia setscrew l-l-radiallj? whereby; to firmlylock the latter i'n such-newly thrdfigffi lock ntl6 frictionally engagedwith} indexed-position; v I I the thfeads I;2 on said. spindle.Obviously;-

Anotherobject-istojroyidean index-fixture well' l now pt fgpmjng:of,smdhousingv oilm l economical-form permitting adjust spindle 6-withcomplementary: tapered sections mentof the md x pe n as shown makes itpossibl to'take-up any-wear? n obflect M ro a v lci wofethei-interengagedsurtwessaridvth i ye mfl lockin adapted wedge hintelr nateailllooseneswn siich' rotary corihc on T dentalspacesintheratchet wheelandt-hus e1imi-- frontv'fidiof sziidis'pind'i 1's: tre'g natet loosenessof the parts: when-i-nan: indexed e m m posi 1011.

Another object isto provide? an 'indexfixture mg assemm in which theaforesaid movable'elementwof the fluid-power device comprises areciprbcatmgiraclel' in? engagement with'- a gear segmentv on. the":ratchet. mechanism, said ra'ck" being in the fomt I of an" aiiii'ularlygrooved rod whefeby rdtaiiy d-is' position threof abbiiit it'sownaxie-aiia iatrat F1 s; 31am 4 are sane new;

beiriaxially retained on said spindle as'by means of 1ock-mitlflandspindle'mit'fl between wli'lch nuts: said pawl support' member" I 5 and"ratche 13h wheel l 5 raredis'pos'ecl'.- Aswiil- -liereihafter e g'if-ully appeari-ritcht wlil Wand spiiidle S stitute a driven memberwhereas said pawl support member operates as a driving member.

Said pawl support member |5 comprises a gear segment l8 concentric withthe axis of rotation of said member and a radially projecting lug I!) towhich a driving pawl 29 is pivotally mounted through the intermediary ofa pawl bolt 2| threaded into said lug and provided with a snap ring 22retaining said pawl on said bolt. The end 23 of said pawl is adapted tobe engaged in one of the interdental spaces or notches 24 in theperiphery of said ratchet wheel I6 and is so formed as to permitrelative rotation of said ratchet wheel and pawl support member in onedirection only. A torsion spring 25 around the bolt 2| having itsaxially directed ends fitting in holes in said pawl and lug is operativeto rotate the pawl to a position with the end thereof disposed in aninterdental space 24.

Bolted or otherwise attached to said pawl support member I5 is anarcuate cam plate 26 provided with a cam surface 21 engageable with theinner end 28 of a locking plunger or lock member 29 which is radiallyreciprocably mounted on said housing. Said locking plunger 29 isreciprocable in a bore formed in the radial bosses 39 and 3| on said.housing and is held against rotation about its own axis as by means of aset screw 32 having the point thereof slidably fitting in alongitudinally extending slot or groove 33 formed in said plunger. Saidplunger is urged radially inward by means of the compression spring 34interposed between said plunger and a cap 35 closing the outer end ofthe boss 3|. As shown, the inner end of said plunger 29 is slightlytapered on its opposite sides, viz. of wedge shape of included angle of6, for example, and the end surface 36 thereof is also at an anglerelative to the axis of the plunger to facilitate entry of said plungerend in the interdental spaces or notches 24 between the teeth of ratchetwheel iii. The teeth of said ratchet wheel are shaped similar to the endof the plunger so as to be complementary therewith and to wedgedlyreceive the wedge shaped end of said plunger. As shown, the cam surface21 of said cam plate 26 is such that the plunger end surface 36 is freetherefrom when the plunger is in looking engagement with said ratchetwheel.

As shown, rotation of the pawl support member I5 in a counterclockwisedirection as viewed in Fig. 1 will effect engagement of the cam surface21 of cam plate 26 with the inner end 28 of said plunger 29 to therebyforce said plunger radially outward relative to the ratchet wheel andthus disengage the plunger from the respective interdental space 24 insaid wheel.

vIn order to hold ratchet wheel |6 against rotation during suchcounterclockwise rotation of pawl support member Hi there is provided aspring actuated holding pawl 3'! pivotally supported on a boss 38 raisedfrom the bottom of recess 2 in said housing I. Said last-named pawl 31is identical to pawl 2| and arranged as shown to permit clockwiserotation of said ratchet wheel |6 through said first pawl 2| and supportmember l5. In the case of pawl 31 the bolt 2| on which the pawl ispivoted is threaded into a plate 39, said plate being secured to boss 38as by screws 49 passing through elongated holes in said plate andthreaded into boss 38. By so adjustably carrying pawl 31 it can beaccurately positioned with reference to pawl 2| and to the interdentalspaces ,24 inratchet wheel IS.-

The lug IQ of said pawlsupport member I5 is engageable with a stop pin4| in said housing to limit the extent of counterclockwise movement ofsaid paw1 support member I5, said stop pin being insertable in any oneof a plurality of openings 42 whereby the indexing movement mayconstitute, in the form of the invention illustrated, the angle between2, 3, 4, and 5 teeth of the ratchet wheel.

Oscillation of said pawl support member l5 in opposite directions iseffected by reciprocation of the movable element 43 of a fluid powerdevice, said fiuid power device as herein illustrated comprising coaxialcylinders 44 and 45 formed in housing of different diameters and amovable element 43 in the nature of pistons 46 and 41 respectivelyreciprocable in said cylinders and having a common piston rod 48therebetween formed with annular grooves 49 of shape for engagement withthe teeth of gear segment I8 of said pawl support member I5. Obviouslywith an arrangement as shown the rotary or lateral disposition of saidpiston rod 48 and pistons 46 and 41 does not effect any misalignmentbetween the grooves 49 and the teeth of the gear segment |8 as would bethe case if a common gear rack were substituted for the annularlygrooved rod 48. It will be evident that in lieu of a piston rod providedwith annular grooves 49 the same may be provided with a worm of shapefor engagement with helical teeth of a gear segment, such latterarrangement being desirable in some instances as where it may benecessary to change the relationship of the rod 48 relative to thesupport member l5.

From Fig. 1 it can be seen that admission of fiuid under pressurethrough the port 50 of the head 5| of cylinder 44 will cause piston rod48 to shift toward the right and thereby rotate pawl support member l5in a counterclockwise direction until lug l9 engages stop pin 4|. Suchcounterclockwise rotation of the pawl support member i5 causes similarrotation of cam 26 and consequent withdrawal of the locking plunger 29from between the teeth of ratchet wheel l6. During' suchcounterclockwise movement of the pawl Support member l5, pawl 2| thereonpasses over the teeth of the ratchet wheel and the other pawl 31 holdssaid ratchet wheel against counterclockwise rotation with said supportmember.

Now, when fluid under pressure is admitted into cylinder 45 through theport 52 in cylinder head 53 the resulting lefthand movement of pistonrod 48 effects clockwise rotation of pawl support member l5 andcorresponding clockwise rotation of ratchet wheel 6 through the drivingengagement of pawl 2| with said wheel and the passing over of pawl 31over th teeth of the ratchet wheel. During such rotation of pawl supportmember I5 the cam surface 21 of cam plate 26 permits compression spring34 to urge locking plunger 29 into wedging and locking engagement in theparticular interdental space 24 of the ratchet wheel then opposite theinner end 28 of said plunger. Thus, such clockwise rotation of ratchetwheel I6 correspondingly rotates spindle 6 and the tool or workpiecesupporting member adapted to be connected thereto. The parts of thefixture are locked firmly in such indexed position until fiuid underpressure is again admitted to actuate the piston rod 48 toward the rightas previously explained.

With respect to Fig. 3, when air or like compressible fluid is employedfor actuating said fluid power device it is preferred that an air flowcontrol valve 54 be included in the piping system to cause the p-istonrod 48 to move with adesiredslovvness ina lefthand direction to minimizeshock on the end 28 of locking plunger 29 and to" permit relativelyrapid movement of thepiston rod 'in a righthand direction. In Fig; 3 thearrow 55' denotes-the direction of fiow of pressure fluid *from acompressor, and the numeral Slide notes a, threewayselector valve forselectively connecting cylinder 45 tothe pressure port- 51' or to; theexhaustport 58;

'I'i e'fiowcontrol'valve: 54*as hereinillustrated comprises;aneedlevalve 59 and a check valve GOc nnectedin parallel wherebywhen-"the valve 56= is inytheposition show-n, pressure fluidcanonlyaflow through the; restricted" passageway oi nee le. valve 59; tocylinder" 45; thus effecting shifting-erred 48 towardthe-left withthe.dc;- siredslowness; such lefthand movement being possible; byreason oi"the larger diameter of cylinder 45 as compared with cylinder 44 to whichlatter cylinder the, pressure line 6!" is; o stan y: c nn ted; Qn theQtherhand, when valve, 56' is actuated, to connected cylinder 45'toexhaust, thewfiuid. acting on piston 46 urges rod 48. toward theright, such righthand move.- ment, Qf 'said rod being at desiredrapidity in. viewflof therelatively free. exhaust of fluid from cylinder45'. through both the. check valve. 60 and, needle... valve 59- Hbwever,when. hydraulic. oil or like liquid is employed, as. the motivatingfiuidfor the fluid power. device. the; piping diagram. should be.

mqdified.asrillustrate d in Fig. 4. With a liquid pressureinedium, ithasbeen found that the flow control valve Mean be dispensed with and afoun-wayvalveBZ- can be; substituted for the valve,.56 fordirectingfluid under pressure from pumpv P to one. cylinder and: discharging the,fluid.- from' the other cylinder; into reservoir: ass

For convenience rigidly mounting the index fixture, the; housing, Ithereofis formed with ears or;1u gs;'6-3 and withaibase portion 64.

From, the; foregoing description of the construction and operation of anillustrative embodiment of this invention it will be apparent to thos e,skilled in the art to devise various schemes for operating the valves 56and 62 by means of cams or the likein timed relation to the movements of'the' slide or the equivalent of a machine tool. operaticnsjnvolyed. inthe-slotting, of collets for. example; ares:

l'). lndege collet, a. part revolution about; its:- central..,axis-;=.

(2); Engage. cutter and. collet-and shiftrelavtively in axial directionto form a slot in said collet from one end toward the other end;

(3) Disengage collet and cutter;

(4) Index collet to next position;

(5) Engage collet and cutter and shift relatively in opposite axialdirection to form another slot; and

(6) Disengage collet and cutter.

Such operations are repeated until the desired number of slots areformed in the collet. Inasmuch as the present invention is onlyconcerned with an indexing mechanism no specific controls have beendisclosed for efi'ecting other relative movements between a workpieceand tool.

Furthermore, insofar as the primary features of this invention areconcerned the ratchet mechanism may be variously modified including forexample the provision of an internally In essence, the successive.

toothed ratchet wheel. with cooperating Dams; and locking memberand acam track for: actuat ing the locking member in both directions lieu ofthe cam-plate--26 and" spring 34;

In any event there is herein disclosed a-unique formof index fixtureor amost elemental-con struction but yet efiicientlyoperating toaccuratel-y'index' andto immovablyhold; angindexed-position. Also,- thefluid pressure operat,- ing means is such that -the locking ofthe-drivenv member in an: indexed positiondoes not entaili theapplication of undue. forces onthe locking member.

Other modes of applying j the principle of the,- invention may beemployed, change beingmade as regards" the details describedi providedthe; featuresstated in any ofthe; following-claims; orthepequivalentof'su'ch; be employed:

We therefore particularly-point outanddisztinctly claim as ourinvention:

1. In anindex fixture, the comination witha. ratchet mechanismcomprising a driven memher, and a driving member movable in oppositedirections having a one-way driving. connection with. said driven;member, of' a. housing, said, driven member comprising, a spindlerotatable. in said housing and a ratchet. wheel non-rotatab': 1y fixedon. said. spindle, said, driving member. comprising a. pawl. support.member rotatably mounted on said spindle. adjacent. said wheel, andadriving pawl on said. pawl support. member. engageable. in thein-terdental.v spaces in. said wheel when. said pawl support member is,rotated in. the. direction of such, one-wayv drivin con.-

w nection, a,-.positively holding pawl in said. hous ing operative-tohold said wheel against. rotation ina direction opposite .tosuch,one-way driving,

connection, a, locking plunger' in said housing movable, into and out.of locking; engagement. with said wheel, and. a camon said pawl sup,-port member operative. todisengage; said locks ing plungerfromsaidwheel. upon rotation of; said; pawl support member: and driving;pawl. thereon in a-direction opposite to its; one-way. driving;connection with said; wheel, and. spindle.-

2.. In an index fixture; the combination with: a 1 ratchet; mechanism.comprising a. driven; mem-a.

ber, and: a driving member movable in opposite; directions-having a.one-way driving. connections.- with .saiddriyen; member,.. of: a;housing-,.,saidz. drivenw member. comprising :a spindlesrotatableainesaid housing and. a. ratchet?wheelgnonrrotatablvx fixed on said spindle,said driving member com. prising a pawl support; member: rotatablymountedion:saidispindleaadjacentsaidgwheel;and.

a driving pawlion said pawl -supDort;me-mben en1-= gageable in theinterdental spaces in said wheel when said pawl support member isrotated in the direction of such one-way driving connection, apositively holding pawl in said housing operative to hold said wheelagainst rotation in a direction opposite to such one-way drivingconnection, a locking plunger in said housing movable into and out oflocking engagement with said wheel, and a cam on said pawl support mem-,ber operative to sheet engagement of said looking plunger with saidwheel upon predetermined rotation of said wheel and spindle by said pawlsupport member and driving pawl.

3. In an index fixture, the combination with a ratchet mechanismcomprising a driven member, and a driving member movable in oppositedirections having a one-way driving connection with said driven member,of a housing, said driven member comprising a spindle rotatable in saidhousing and a ratchet wheel non-rotatably fixed on said spindle, saiddriving member comprising a pawl support member rotatably mounted onsaid spindle adjacent said wheel, and a driving pawl on said pawlsupport member engageable in the interden-tal spaces in said wheel whensaid pawl support member is rotated in the direction of such one-waydriving connection, a positively holding pawl in said housing operativeto hold said wheel against rotation in a direction opposite to suchone-way driving connection, a locking plunger in said housing movableinto and out of locking engagement with said wheel, and a cam on saidpawl support member operative to disengage said locking plunger fromsaid wheel upon rotation of said pawl support member and driving pawlthereon in a direction opposite to its one-way driving connection withsaid wheel and spindle, said locking plunger being provided with alocking wedge shaped end portion, and said wheel being provided with acomplementary notch for receiving such end portion of said lock member.

4. In an index fixture, the combination with a ratchet mechanismcomprising a driven member, and a driving member movable in oppositedirections having a one-way driving connection with said driven member,of a housing, said driven member comprising a spindle rotatable in saidhousing and a ratchet wheel non-rotatably fixed on said spindle, saiddriving member comprising a pawl support member rotatably mounted onsaid spindle adjacent said wheel, and a driving pawl on said pawlsupport member engageable in the interdental spaces in said wheel whensaid pawl support member is rotated in the direction of such one-waydriving connection, a positively holding pawl in said housing operativeto hold said wheel against rotation in a direction opposite to suchone-way driving connection, a locking plunger in said housing movableinto and out of locking engagement with said wheel, a cam on said pawlsupport member operative to disengage said locking .plunger from saidwheel upon rotation of said pawl support member and driving pawl thereonin a direction opposite to its one way driving connection with saidwheel and spindle, and means for rotating said pawl support member inopposite directions comprising a gear segment on said pawl supportmember, and a cylindrical rod reciprocably supported in said housing andprovided with a series of annular'grooves in mesh with the teeth of saidgear segment.

5. In an index fixture, the combination of a housing, a ratchetmechanism in said housing comprising a driven member rotatably supportedby said housing, and a. driving member rotatable in opposite directionshaving a one-way driving connection with said driven member, and a lockmember mounted in said housing for reciprocation radially into and outof engagement with said driven member, a spring in said housingconstantly urging said lock member toward said driven member, and a camon said driving member operative to engage said lock member and move thesame radially out of engagement-with said driven member upon rotation ofsaid driving member in a direction opposite to its one-way drivingconnection with said driven member, said lock member being provided witha locking wedge shaped end portion, and said driven member beingprovided with a complementary notch for receiving such end portion ofsaid lock member.

6. In an index fixture, the combination of a housing, a ratchetmechanism in said housing comprising a driven member rotatably supportedby said housing, and a driving member rotatable in opposite directionshaving a one-way driving connection with said driven member, and a lockmember mounted in said housing for reciprocation radially into and outof engagement with said driven member, a spring in said housingconstantly urging said lock member toward said driven member, and a camon said driving member operative to engage said lock member and move thesame radially out of engagement with said driven member upon rotation ofsaid driving member in engagement with said driven member-j MILTON L.BENJAMIN. FRANKLYN E. WINNEN.

REFERENCES CITED The following references are of record in the file ofthis patent;

UNITED STATES PATENTS Number Name Date 1,404,243 Stewart et a1. Jan. 24,1922 1,840,300 Archea Jan. 12, 1932 1,909,766 Johnson et al May 16, 19332,261,052 Coflin et a1 Oct. 28, 1941 2,262,103 Laessker Nov. 11, 1941

